1. Field of the Invention
The present invention relates to a ceramic substrate containing a ceramic material, and an electronic device.
2. Description of the Related Art
As an insulating substrate on which electronic components such as a power semiconductor device are mounted, a ceramic substrate formed of a silicon nitride sintered body is used. The silicon nitride sintered body has a relatively large mechanical strength and thermal conductivity and hence is used as the insulating substrate. In the silicon nitride sintered body, an oxide of calcium, magnesium, aluminum, yttrium, or the like is used as a sintering aid (see, for example, Patent Literatures 1 and 2).
The electronic components mounted on the insulating substrate are thermally connected to a heat dissipator formed of a metal through the insulating substrate and the like so as to dissipate heat from the electronic components through the heat dissipator to the outside. Further, the electronic components are electrically connected to an external electric circuit through a conductive connecting material such as a lead terminal.